In a large pot, combine the bones, vinegar, and any optional additions with 6 quarts of water and slowly bring to a gentle boil over medium heat. Skim off any foam that rises to the top, reduce the heat to a low simmer, and cook for the amount of time indicated in the chart below, based on the type of broth you are making. When the cooking time is complete, strain the broth through a fine-mesh sieve.